The treatment of waste fluids, e.g. processing plant liquors, containing both sulfur compounds and organic (carbon) compounds by combustion so as to eliminate these environmental pollutants, is known.
In such processes, the waste, e.g. a solution, suspension slurry or even flowable solid, is burnt to produce an exhaust gas which is subjected to physical or chemical scrubbing to eliminate contaminants or pollutants present in the exhaust gas, e.g. sulfur dioxide.
In such processes the combustion products of the exhaust gas include carbon dioxide and sulfur dioxide, as noted, and it is essential to remove practically all of the sulfur dioxide. The processes have been employed to increasing extents in the cellulose industry for the processing of cellulose digestion liquors (see WOCHENBLATT FOR PAPIERFABRIKATION, 23/24, 1972, pages 910 ff.).
The combustion-sustaining gas required for these processes is atmospheric oxygen. Since the concentration of the contaminants in the exhaust gas and therefore their partial pressure is generally low, the requirements for effective removal of these contaminants (e.g. SO.sub.2) are considerable. In other words, in order to reduce the concentration of the toxic contaminants of the exhaust gas stream to an environmentally acceptable level when the latter stream is discharged into the atmosphere, the scrubbing must be rigorous, the cooling to separate liquid from the gas phase during the washing must be considerable or washing and scrubbing agents must be used with high tendencies to pick up the traces of the toxic components.
These requirements indicate expensive scrubbing apparatus, high energy losses because of the degree of cooling required, and large expenses connected with the use of high-quality scrubbing agents.